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									The impact of acute myocardial infarction on left ventricular systolic function
Koçinaj Dardan1§, Bakalli Aurora1, Gashi Masar1, Berisha Merita2, Koçinaj Allma1,
Berisha Blerim1, Krasniqi Xhevdet1.
1
  University Clinical Centre of Kosovo, Prishtina, Republic of Kosovo
2
  National Institute of Public Health of Kosovo, Prishtina, Republic of Kosovo


Email addresses:
DK: dall_k@yahoo.com
AB: abakalli@hotmail.com
MG: masargk@yahoo.com
MB: meritaberisha@yahoo.com
AK: allmakocinaj@yahoo.com
BB: drblerimberisha@yahoo.com
XK: xhevdeti_16@hotmail.com
§
  Corresponding author:
Koçinaj Dardan
University Clinical Centre of Kosovo
Rrethi i Spitalit p.n.
10000 Prishtina, Republic of Kosovo
Tel. +37744312144
e-mail: dall_k@yahoo.com

ABSTRACT
During acute myocardial infarction left ventricular systolic function is an important
prognostic factor whose worsening is still frequent despite the therapeutic approach. We
aimed to estimate the incidence of left ventricular systolic dysfunction among patients
experiencing acute myocardial infarction. The study involved 154 consecutive patients
admitted at Coronary Care Unit. The study design was based upon the collection of
patient histories, clinical examination and other complementary tests. In overall study
population, predominantly with male gender, the incidence of left ventricle systolic
dysfunction was 42.3%, which correlated with myocardial damage, electrocardiography
changes, myocardial enzymes, and myocardial wall motion. Transthoracic
Echocardiography represents a valuable tool and left ventricular ejection fraction should
be evaluated in all patients experiencing acute myocardial infarction since the incidence
of left ventricular dysfunction in patients with Acute Myocardial Infarction remains
relatively high.

Key words: acute myocardial infarction, left ventricle function, echocardiography.
INTRODUCTION
The assessment of left ventricular function following acute myocardial infarction (AMI)
has been shown in many studies to give important prognostic information as well as
helping to guide therapeutic intervention. Although Wall Motion Score Index (WMSI)
assessed by echocardiography is a relatively easily obtained marker of global left
ventricular (LV) dysfunction, a greater degree of wall motion abnormality must take
place before a lower ejection fraction (EF) occurs. Several studies have shown that
WMSI correlates well with LV EF and some have directly compared it in the assessment
of prognosis after myocardial infarction. [1]

Patients with AMI who have diabetes have an increased risk of death. It has also been
shown that undiagnosed glycemic abnormalities are common in patients with an acute
myocardial infarction, which are detectable early in the post infarction period. These
disorders in the early phase of an acute myocardial infarction could be used as early
markers of high-risk patients. [2] Nevertheless, the issue of whether glucose
concentrations below the diabetic threshold may be predictive of increased cardiovascular
risk has not yet been fully elucidated. Some findings suggest the increased mortality rate
among nondiabetic coronary patients with impaired fasting glucose [3] known as a direct
and independent risk factor. The mechanisms are attributed in the production of free
radicals, which favours the development of an endothelial dysfunction. [4, 5] Also, on the
other hand, the risk of acute coronary events is significantly increased and is similar to
that of patients without diabetes who have already had a myocardial infarction.

Nowadays diabetics are accounting for a greater proportion of the global population,
increasing the number of hospital admissions, being at heightened risk of heart failure,
cardiogenic shock and death. [6]

On the other hand, among other laboratory parameters, although there is an evidence of
increase in the number of white blood cells, still few data exist about the relationship of
circulating granulocyte-macrophage colony stimulating factor and some soluble adhesion
molecules to the severity of AMI and the pathophysiological events of post-infarction LV
dysfunction. [7]

Some other techniques, as quantitative analysis of color kinesis images, provide easy
information of endocardial excursion, enabling fast, objective and more accurate
evaluation of LV regional wall motion. [8]
GOAL
The main aim of our study was to estimate the incidence of LV systolic dysfunction
among patients experiencing acute myocardial infarction. We also had a purpose to
determine the most exposed gender, age, previous related diseases, and early in-hospital
mortality. Finally we aimed to evaluate the relationship between extension of myocardial
damage at ECG, myocardial enzymes, WBC and myocardial regional contractility
involvement.
METHODS
Population




                                                                                         2
This cross sectional prospective study involved 154 consecutive patients aged <75 years
admitted at Coronary Care Unit of our Institution for Acute Coronary Syndromes and
treated by noninvasive management protocol.
Study design
The study design was based upon the collection of patient histories, clinical examination
and laboratory data, the ECG, and the transthoracic echocardiography.
Diagnostic criteria
Acute myocardial infarction (AMI) was defined by elevated cardiac markers associated
with more than one of the following characteristics: symptoms of myocardial ischaemia,
development of ST-T abnormalities considered of ischaemic origin,and/or development
of new Q waves.
Hypertension and/or Diabetes mellitus were reported either if a patient had a history of
the disease or documented an ongoing treatment. Previous Myocardial Infarction was
encountered by previous history, documentation or present ECG.
Transthoracic echocardiography
All patients underwent conventional transthoracic echocardiography using commercially
available equipment (Phillips iE 33).
Transthoracic echocardiographic (TTE) examinations and measurements were performed
with the subject in the left lateral decubitus position, according to the recommendations
of the American Society of Echocardiography [9].
Left ventricular end-diastolic/end-sistolic diameters, wall (septal and posterior) thickness
have been measured from parasternal M-mode recordings according to standard criteria.
Left ventricular ejection fraction (EF%) was determined from apical views with a
modified Simpson’s rule. Left ventricle systolic function was considered impaired if
ejection fraction <45 %.
Assessement of wall motion abnormalities (WMA) was made according to the
recommendation of AHA Writing Group on Myocardial Segmentation and Registration
for Cardiac Imaging (2002). WMSI was derived by grading the wall motion of individual
myocardial segments (motion and systolic thickening) and dividing the total score by the
number of analyzable 17-segments [9, 10]. The function of each segment was confirmed
in multiple views. Segment scores were as follows: normal or hyperkinesis =1,
hypokinesis = 2, akinesis (negligible thickening) = 3, dyskinesis (paradoxical systolic
motion) = 4 and aneurysmal (diastolic deformation) = 5.
Statistical analyzes
Collected data were analyzed, presented by tables and figures, statistical parameters
(mean, SD, etc.) were calculated and tested. These data are discussed with relevant data
from the references. Correlation between variables was calculated using Person
correlation test. P value < 0.05 was considered of statistical significance.
RESULTS
Basic demographic data of the study population
Total number of the examined population was 154 with a mean age 61.4 (±11.8) years.
Male gender was predominant in our overall study population, accounting 64.3%.
All the patients were diagnosed as acute myocardial infarction. Around one third of them
(31,2%) had arterial hypertension, 31 (20.1%) had diabetes mellitus and 9.1% had
previously suffered a myocardial infarction.




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Based on electrocardiography, the acute episode of myocardial infarction appeared to
happen mostly in the anterior left myocardial wall, while the non anterior AMI was found
on 43.5% of this population. The early In-hospital mortality occurred on 9 (5.8%) out of
the patients included in the study, (Table 1.) two of them where diabetics with LV
systolic dysfunction.

Table 1. Basic Characteristics of the Study Population
          Modalities             N              %
              M                  99            64.3
      Average age±SD                     61.4 ±11.8
        Hypertension             48            31.2
      Diabetes mellitus          31            20.1
         Previous MI             14             9.1
      AMI non anterior           67            43.5
 Early In-Hospital Mortality      9             5.8

Impaired left ventricle systolic function
In overall study population, predominantly with male gender, the incidence of left
ventricle systolic dysfunction was 42.3%. (Figure 1.)

Figure 1. Left ventricular systolic dysfunction among the analyzed patients




                                                    With
                                                   42.3%


       Without
        57.7%




The average value of ejection fraction of all analyzed patients was 49.4±9.5%. In
patients with low ejection fraction, nine of them were diabetics, whereas three of them
have ended up fatally.
Correlation of several parameters of our study population
There was a significant high correlation r = 0.87, p<0.001 between left ventricle ejection
fraction and WMSI, and a negative medium correlation r = -0.4, p<0.001 between left
ventricle ejection fraction and CK-MB. (Figure 2.)




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                              Figure 2. Correlation between LVEF and CK-MB

    7

                                                                                  p<0.001
    6




    5




    4
 CK-MB



    3




    2




    1




    0
        0      10        20             30          40         50            60    70       80
                                                   EF




Opposite same correlation r = 0.4, p<0.001 has been found between WBC and CK-MB
(Figure 3.), while a significant correlation, r = 0.7, p<0.001 of CK and its isoenzyme CK-
MB. (Figure 4.)




                                                                                                 5
              Figure 3. Correlation of WBC and CK-MB in our population

  7

                                                                             p<0.001
  6




  5




   4
CK-MB



  3




  2




  1




  0
      0   1               2               3                4             5             6
                                         WBC




               Figure 4. Level of enzymes CK and CK-MB in correlation

  7

                                                                             p<0.001
  6




  5




   4
CK-MB



  3




  2




  1




  0
      0   1               2               3                4             5             6
                                         CK




                                                                                           6
A negative low correlation was found between LVEF and severity of AMI. The latter had
also low correlation with WBC. (Figure 5. and 6.)

                     Figure 5. LVEF in relationship with severity of Acute Myocardial Infarction

      80



      70



      60



      50


 EF
      40



      30



      20



      10



          0
               0      1              2             3                     4       5                 6   7
                                                       Severity of AMI




                   Figure 6. Relationship between severity of Acute Myocardial Infarction and WBC

      7




      6




      5




   4
 WBC



      3




      2




      1




      0
           0          1             2              3                     4       5                 6   7
                                                       Severity of AMI




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DISCUSSION

The risk of heart failure is particularly high in diabetic patients with MI and was the most
common cause of death, also reported in the DIGAMI (Diabetes mellitus Insulin-Glucose
infusion in Acute Myocardial Infarction) study. [11, 12] One fifth of our population had
diabetes but there was no difference in term of impaired left ventricular function related
to the rest of study group, but still there is evidence of relatively aged population even
with history of previous MI which also increases the risk of post AMI complications
comparable to diabetes. On the other side, Parissis et al. reported a significant elevation,
with the highest values, of plasma GM-CSF and soluble adhesion molecules, in patients
with AMI complicated by heart failure manifestations. Though, they may contribute to
the pathophysiology of the disease and post-infarction cardiac dysfunction. [7] Our data
relied on a single value of WBC, which in general showed a low correlation with severity
of AMI based on ECG changes, but still a good correlation to CK-MB isoenzyme.

WMSI as an easily measurable marker of LV function closely correlates with EF post
AMI. A closer correlation is reported for anterior infarctions before discharge. WMSI of
0.6, 0.8, and 1.1 correspond best to EF 45%, 40%, and 35%, respectively based on RNV
(radionuclide ventriculography). [1] Our data suggest a significant high correlation of
those two parameters.
STUDY LIMITATION
Limitation of the present study is the relatively small study group and no repetition of
Echocardiography study.
CONCLUSIONS
The incidence of left ventricle dysfunction in patients with Acute Myocardial Infarction
remains relatively high. Heart failure commonly complicates acute myocardial infarction
in patients with diabetes. The level of myocardial injury correlates with development of
left ventricular failure and regional contractility involvement. Transthoracic
Echocardiography represents a valuable tool and left ventricular ejection fraction should
be carefully evaluated in all patients experiencing acute myocardial infarction. At present
prevention of myocardial infarction remains the main management goal for protecting
people with diabetes from the risk of heart failure.
ABREVIATIONS
AMI- Acute Myocardial Infarction
WMSI- Wall Motion Score Index
LV- Left Ventricle
EF- Ejection Fraction
CCU- Coronary Care Unit
ECG- Electrocardiography
WBC- White Blood Cells
TTE- Transthoracic Echocardiography
WMA- Wall Motion Abnormalities
CK-MB- Creatine Kinaze- MB isoenzyme
CK- Creatine Kinaze
DIGAMI- Diabetes mellitus Insulin-Glucose infusion in Acute Myocardial Infarction
GM-CSF- Granulocyte-Macrophage Colony Stimulating Factor
RNV- Radionuclide Ventriculography


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CONSENT
Written informed consent was obtained from each patient for publication of the study.
COMPETING INTERESTS
The authors declare that they have no competing interests.
AUTHORS’ CONTRIBUTIONS
DK analyzed and interpreted the data and was a major contributor in writing the
manuscript. AB analyzed the data and contributed in writing the manuscript. BK
analyzed and interpreted the data. XK analyzed and interpreted the data. All authors read
and approved the final manuscript.
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